Channel sounding information feedback method, user equipment, and base station

ABSTRACT

Embodiments provide a channel sounding information feedback method, user equipment, and a base station. The method includes: determining, by UE, a first period used to periodically report channel sounding information; and periodically sending, by the UE based on received preset downlink control information DCI that is sent by a base station, the channel sounding information by using the first period as a sending period. System overheads can be reduced, a configuration response can be improved, and spectrum utilization of a system can be improved while periodic feedback of indication is reduced.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/022,723, filed on Jun. 29, 2018, which is a continuation ofInternational Application No. PCT/CN2016/105776, filed on Nov. 14, 2016,which claims priority to Chinese Patent Application No. 201511033853.6,filed on Dec. 31, 2015. All of the afore-mentioned patent applicationsare hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to the field of communicationstechnologies, and in particular, to a channel sounding informationfeedback method, user equipment, and a base station.

BACKGROUND

In a Long Term Evolution (LTE) communications system, channel soundinginformation is obtained by user equipment (UE) by sounding a downlinktransmission channel and quantizing a sounding result and is reported bythe user equipment to a base station, so that the base station canobtain an interference status of downlink transmission.

The channel sounding information includes a channel quality indicator(CQI) and a channel sounding reference signal (SRS). UE sounds adownlink transmission channel to obtain a CQI, and feeds back the CQI toa base station on an uplink channel. The base station determines amodulation and coding scheme of the UE based on the fed back CQI. Inaddition, the base station estimates channel state information of adownlink channel by using an uplink SRS and reciprocity between theuplink channel and the downlink channel, to obtain a channel matrix of amulti-transceiver-unit system. Based on the channel matrix, co-frequencyand co-time transmission of a plurality of UEs can be implemented on thebase station by using a precoding technology, thereby improving spectrumutilization of the system.

In a current standard, feedback of a CQI and an SRS includes two types:periodic feedback and aperiodic feedback.

For periodic CQI feedback, a CQI is carried by using a physical uplinkcontrol channel (PUCCH), and a time interval of the feedback isimplemented through semi-static configuration by using higher layerRadio Resource Control (RRC) signaling. For aperiodic CQI feedback, aCQI is carried by using a physical uplink shared channel (PUSCH). Thefeedback is triggered by receiving downlink control information (DCI).Each time the UE is triggered, the UE feeds back all sounded CQIs at atime by using the PUSCH. Frequency of periodic feedback of an SRS isconfigured by using higher layer RRC. Aperiodic feedback of an SRS istriggered by receiving DCI. After each trigger, the UE transmits the SRSonly once on the last symbol of a configured subframe.

In a future evolved cellular network system, a very high requirement isimposed on channel sounding information obtained by a base station. Thatis, sounding frequency of the channel sounding information needs to beincreased. Therefore, a feedback interval of a CQI or an SRS needs to beshortened. However, dynamically changing feedback frequency byincreasing a quantity of times of aperiodic feedback or by using RRCconfiguration leads to problems that overheads are increased and aconfiguration response is not timely, and consequently, overall spectrumutilization of the system is affected.

SUMMARY

The present disclosure provides a channel sounding information feedbackmethod, user equipment, and a base station, to reduce system overheads,improve a configuration response, and improve spectrum utilization of asystem while periodic feedback of indication is reduced.

According to a first aspect, a channel sounding information feedbackmethod is provided, including: determining, by user equipment UE, afirst period used to periodically report channel sounding information;and periodically sending, by the UE based on received preset downlinkcontrol information DCI that is sent by a base station, the channelsounding information by using the first period as a sending period.

With reference to the first aspect, in a first possible implementationof the first aspect, the method further includes: determining, by theUE, a second period used to periodically report channel soundinginformation; and the periodically sending, by the UE, the channelsounding information by using the first period as a sending periodincludes: periodically sending, by the UE, the channel soundinginformation by using the first period and/or the second period as asending period.

With reference to the first possible implementation of the first aspect,in a second possible implementation of the first aspect, before the UEreceives the preset downlink control information DCI that is sent by thebase station, the method further includes: periodically sending, by theUE, the channel sounding information by using the first period as asending period; and the periodically sending, by the UE, the channelsounding information by using the second period as a sending periodincludes: switching, by the UE, to periodically send the channelsounding information by using the second period as a sending period.

With reference to the second possible implementation of the firstaspect, in a third possible implementation of the first aspect, apriority of the channel sounding information sent by using the secondperiod is greater than a priority of the channel sounding informationsent by using the first period; and the switching, by the UE, toperiodically send the channel sounding information by using the secondperiod as a sending period includes: if the UE needs to send the channelsounding information by using the first period and the second period asa sending period separately at a same moment, switching, by the UE tosend the channel sounding information corresponding to the second periodat the moment by using the second period as a sending period.

With reference to the first possible implementation of the first aspect,in a fourth possible implementation of the first aspect, before the UEreceives the DCI that is sent by the base station, the method furtherincludes: configuring, by the UE, a first timer associated with thefirst period and/or a timer associated with the second period.

With reference to the fourth possible implementation of the firstaspect, in a fifth possible implementation of the first aspect, theperiodically sending, by the UE, the channel sounding information byusing the second period as a sending period includes: starting, by theUE, the second timer; and when the second timer expires, stopping, bythe UE, periodically sending the channel sounding information by usingthe second period as a sending period, and restoring to periodicallysend the channel sounding information by using the first period as asending period.

With reference to the fourth possible implementation of the firstaspect, in a sixth possible implementation of the first aspect, theperiodically sending, by the UE, the channel sounding information byusing the first period as a sending period includes: starting, by theUE, the first timer; and when the first timer expires, stopping, by theUE, periodically sending the channel sounding information by using thefirst period as a sending period.

With reference to the first possible implementation of the first aspect,in a seventh possible implementation of the first aspect, theperiodically sending, by the UE, the channel sounding information byusing the first period and/or the second period as a sending periodincludes: determining, by the UE, indication information in the receivedpreset DCI, where the indication information is used to indicate thefirst period and/or the second period; and when the indicationinformation is information used to start the first period and/or thesecond period, periodically sending, by the UE, the channel soundinginformation by using the first period and/or the second period as asending period.

With reference to the seventh possible implementation of the firstaspect, in an eighth possible implementation of the first aspect, themethod further includes: when the indication information is used todisable feedback of the channel sounding information, and the UE usesthe second period as a sending period, restoring, by the UE, toperiodically send the channel sounding information by using the firstperiod as a sending period.

With reference to the seventh possible implementation of the firstaspect, in a ninth possible implementation of the first aspect, themethod further includes: when the indication information is used todisable feedback of the channel sounding information, and the UE usesthe first period as a sending period, stopping, by the UE, sending thechannel sounding information by using the first period as a sendingperiod.

With reference to any one of the seventh possible implementation of thefirst aspect to the ninth possible implementation of the first aspect,in a tenth possible implementation of the first aspect, the indicationinformation is carried by using a field in the preset DCI; and the fieldin the preset DCI includes at least one of the following: a downlinkassignment index DAI field of the DCI; a resource block assignmentResource block assignment field in DCI format Format 1A controlsignaling; and a CSI request field and an SRS request field in a DCIformat 0 and/or the DCI format 4.

With reference to any one of the seventh possible implementation of thefirst aspect to the ninth possible implementation of the first aspect,in an eleventh possible implementation of the first aspect, thedetermining, by the UE, indication information in the received presetDCI includes: if the preset DCI is the resource block assignment fieldin the DCI format 1A control signaling, and a value in the resourceblock assignment field is a specified value, obtaining designatedlocation information in a modulation and coding scheme MCS field in theDCI format 1A control signaling; and using the designated locationinformation as the indication information.

With reference to the tenth possible implementation of the first aspect,in a twelfth possible implementation of the first aspect, theperiodically sending, by the UE, the channel sounding information byusing the first period and/or the second period as a sending periodincludes: if the preset DCI is the CSI request field and the SRS requestfield in the DCI format 0 and/or the DCI format 4, triggering, by theUE, aperiodic channel sounding information once; and after sending theaperiodic channel sounding information, periodically sending, by the UE,the channel sounding information by using the first period and/or thesecond period as a sending period.

With reference to any one of the first aspect to the twelfth possibleimplementation of the first aspect, in a thirteenth possibleimplementation of the first aspect, the channel sounding informationincludes a channel sounding information indicator CQI and/or a channelsounding reference signal SRS.

According to a second aspect, a channel sounding information feedbackmethod is provided, including: sending, by a base station, presetdownlink control information DCI to user equipment UE; and receiving, bythe base station, channel sounding information sent by the UE, where thechannel sounding information is periodically sent by the UE by using afirst period and/or a second period as a sending period, and the firstperiod and the second period are a sending period used by the UE to sendthe channel sounding information.

With reference to the second aspect, in a first possible implementationof the second aspect, the sending, by a base station, preset DCI to UEincludes: sending, by the base station, the preset DCI to the UE, wherethe preset DCI includes indication information, and the indicationinformation is used to indicate the first period and/or the secondperiod.

With reference to the first possible implementation of the secondaspect, in a second possible implementation of the second aspect, theindication information includes one of the following: information usedto start the first period and/or the at least one second period; andinformation used to end the first period and/or the at least one secondperiod.

With reference to the first or the second possible implementation of thesecond aspect, in a third possible implementation of the second aspect,the preset DCI includes a downlink assignment index DAI field of theDCI; and the sending, by the base station, the preset DCI to the UEincludes: sending, by the base station, the preset DCI to the UE, wherewhen the DAI field of the DCI does not carry a bundled feedbackacknowledgement/negative acknowledgement ACK/NACK, the base station setsthe DAI field to carry the indication information used to indicatefeedback of the channel sounding information

With reference to the first or the second possible implementation of thesecond aspect, in a fourth possible implementation of the second aspect,the preset DCI includes a resource block assignment Resource blockassignment field in the DCI format Format 1A control signaling; and thesending, by the base station, the preset DCI to the UE includes:setting, by the base station, a value in the resource block assignmentfield in the DCI format 1A control signaling to a specified value;setting, by the base station, designated bit information in a modulationand coding scheme MCS field in the DCI format 1A control signaling,where the specified value and the designated bit information are used toindicate the indication information for indicating the first periodand/or the second period; and sending, by the base station, the DCIformat 1A control signaling carrying the indication information to theUE.

With reference to the first or the second possible implementation of thesecond aspect, in a fifth possible implementation of the second aspect,the preset DCI includes a CSI request field and an SRS request field ina DCI Format 0 and/or the DCI format 4; and the sending, by the basestation, the preset DCI to the UE includes: setting, by the basestation, the CSI request field and the SRS request field in the DCIformat 0 and/or the DCI format 4 control signaling to a specified value,where the specified value is the indication information for indicatingthe first period and/or the second period; and sending, by the basestation, the DCI format 0 and/or DCI format 4 control signaling carryingthe indication information to the UE.

With reference to any one of the second aspect to the fifth possibleimplementation of the second aspect, in a sixth possible implementationof the second aspect, the channel sounding information includes achannel sounding information indicator CQI and/or a channel soundingreference signal SRS.

According to a third aspect, user equipment is provided, including: aprocessing unit, configured to determine a first period used toperiodically report channel sounding information; and a transceiverunit, configured to receive preset downlink control information DCI thatis sent by a base station, where the processing unit is furtherconfigured to periodically send, by using the transceiver unit and basedon the received preset downlink control information DCI that is sent bythe base station, the channel sounding information by using the firstperiod as a sending period.

With reference to the third aspect, in a first possible implementationof the third aspect, the processing unit is further configured to:determine a second period used to periodically report channel soundinginformation; and periodically send, by using the transceiver unit, thechannel sounding information by using the first period and/or the secondperiod as a sending period.

With reference to the first possible implementation of the third aspect,in a second possible implementation of the third aspect, the processingunit is further configured to: before the preset DCI is received,periodically send, by using the transceiver unit, the channel soundinginformation by using the first period as a sending period; and after thepreset DCI is received, switch to periodically send the channel soundinginformation by using the second period as a sending period.

With reference to the second possible implementation of the thirdaspect, in a third possible implementation of the third aspect, apriority of the channel sounding information sent by using the secondperiod is greater than a priority of the channel sounding informationsent by using the first period; and the processing unit is specificallyconfigured to: if the UE needs to send the channel sounding informationby using the first period and the second period as a sending periodseparately at a same moment, switch, by the UE, to send, by using thetransceiver unit, the channel sounding information corresponding to thesecond period at the moment by using the second period as a sendingperiod.

With reference to the first possible implementation of the third aspect,in a fourth possible implementation of the third aspect, the processingunit is further configured to configure a first timer associated withthe first period and/or a timer associated with the second period.

With reference to the fourth possible implementation of the thirdaspect, in a fifth possible implementation of the third aspect, theprocessing unit is specifically configured to: start the second timer;and when the second timer expires, stop periodically sending the channelsounding information by using the second period as a sending period, andrestore to periodically send the channel sounding information by usingthe first period as a sending period.

With reference to the fourth possible implementation of the thirdaspect, in a sixth possible implementation of the third aspect, theprocessing unit is specifically configured to: start the first timer;and when the first timer expires, stop periodically sending the channelsounding information by using the first period as a sending period.

With reference to the first possible implementation of the third aspect,in a seventh possible implementation of the third aspect, the processingunit is specifically configured to: determine indication information inthe received preset DCI, where the indication information is used toindicate the first period and/or the second period; and when theindication information is information used to start the first periodand/or the second period, periodically send, by using the transceiverunit, the channel sounding information by using the first period and/orthe second period as a sending period.

With reference to the seventh possible implementation of the thirdaspect, in an eighth possible implementation of the third aspect, theuser equipment further includes: the processing unit is specificallyconfigured to: when the indication information is used to disablefeedback of the channel sounding information, and the UE uses the secondperiod as a sending period, restore to periodically send, by using thetransceiver unit, the channel sounding information by using the firstperiod as a sending period.

With reference to the seventh possible implementation of the thirdaspect, in a ninth possible implementation of the third aspect, theprocessing unit is further configured to: when the indicationinformation is used to disable feedback of the channel soundinginformation, and the UE uses the first period as a sending period, stopsending the channel sounding information by using the first period as asending period.

With reference to any one of the third aspect to the ninth possibleimplementation of the third aspect, in a tenth possible implementationof the third aspect, the indication information is carried by using afield in the preset DCI; and the field in the preset DCI received by thetransceiver unit includes at least one of the following: a downlinkassignment index DAI field of the DCI, a resource block assignmentResource block assignment field in the DCI format Format 1A controlsignaling, and a CSI request field and an SRS request field in the DCIformat 0 and/or the DCI format 4.

With reference to any one of the seventh possible implementation of thethird aspect to the ninth possible implementation of the third aspect,in an eleventh possible implementation of the third aspect, theprocessing unit is specifically configured to: if the preset DCI is aresource block assignment field in the DCI format 1A control signaling,and a value in the resource block assignment field is a specified value,obtain designated location information in a modulation and coding schemeMCS field in the DCI format 1A control signaling; and use the designatedlocation information as the indication information.

With reference to the tenth possible implementation of the third aspect,in a twelfth possible implementation of the third aspect, the processingunit is specifically configured to: if the preset DCI is the CSI requestfield and the SRS request field in the DCI format 0 and/or the DCIformat 4, trigger, by the UE, aperiodic channel sounding informationonce; and after the aperiodic channel sounding information is sent,periodically send, by the UE, the channel sounding information by usingthe first period and/or the second period as a sending period.

With reference to any one of the third aspect to the twelfth possibleimplementation of the third aspect, in a thirteenth possibleimplementation of the third aspect, the channel sounding informationsent by the processing unit by using the transceiver unit includes achannel sounding information indicator CQI and/or a channel soundingreference signal SRS.

According to a fourth aspect, a base station is provided, including aprocessing unit and a transceiver unit. The processing unit isconfigured to: preset downlink control information DCI; send the presetdownlink control information DCI to user equipment UE by using thetransceiver unit; and receive channel sounding information sent by theUE, where the channel sounding information is periodically sent by theUE by using a first period and/or a second period as a sending period,and the first period and the second period are a sending period used bythe UE to send the channel sounding information.

With reference to the fourth aspect, in a first possible implementationof the fourth aspect, the processing unit is specifically configured tosend the preset DCI to the UE by using the transceiver unit, where thepreset DCI includes indication information, and the indicationinformation is used to indicate the first period and/or the secondperiod.

With reference to the first possible implementation of the fourthaspect, in a second possible implementation of the fourth aspect, theindication information sent by the transceiver unit includes one of thefollowing: information used to start the first period and/or the atleast one second period; and information used to end the first periodand/or the at least one second period.

With reference to the first or the second possible implementation of thefourth aspect, in a third possible implementation of the fourth aspect,the preset DCI includes a downlink assignment index DAI field of theDCI; and the processing unit is specifically configured to: send thepreset DCI to the UE, where when the DAI field of the DCI does not carrya bundled feedback acknowledgement/negative acknowledgement ACK/NACK,the base station sets the DAI field to carry the indication informationused to indicate the feedback of the channel sounding information.

With reference to the first or the second possible implementation of thefourth aspect, in a fourth possible implementation of the fourth aspect,the preset DCI includes a resource block assignment Resource blockassignment field in the DCI format Format 1A control signaling; and theprocessing unit is specifically configured to: set a value in theresource block assignment field in the DCI format 1A control signalingto a specified value; set designated bit information in a modulation andcoding scheme MCS field in the DCI format 1A control signaling, wherethe specified value and the designated bit information are used toindicate the indication information for indicating the first periodand/or the second period; and send the DCI format 1A control signalingcarrying the indication information to the UE.

With reference to the first or the second possible implementation of thefourth aspect, in a fifth possible implementation of the fourth aspect,the preset DCI includes a CSI request field and an SRS request field ina DCI format 0 and/or the DCI format 4; and the processing unit isspecifically configured to: set the CSI request field and the SRSrequest field in the DCI format 0 and/or the DCI format 4 controlsignaling to a specified value, where the specified value is theindication information for indicating the first period and/or the secondperiod; and send the DCI format 0 and/or DCI format 4 control signalingcarrying the indication information to the UE.

With reference to any one of the fourth aspect to the fifth possibleimplementation of the fourth aspect, in a sixth possible implementationof the fourth aspect, the channel sounding information received by thetransceiver unit includes a channel sounding information indicator CQIand/or a channel sounding reference signal SRS.

According to a fifth aspect, user equipment is provided, including atransceiver and a processor. The transceiver may implement functions ofthe foregoing transceiver unit, and the transceiver includes aninterface. The processor may implement functions of the foregoingprocessing unit. Details are not described again.

The user equipment may further include a memory, configured to storedata and program code. The processor may obtain the program code fromthe memory, and perform a corresponding procedure based on the obtainedprogram code.

According to a sixth aspect, a base station is provided, including atransceiver and a processor. The transceiver may implement functions ofthe foregoing transceiver unit, and the transceiver includes aninterface. The processor may implement functions of the foregoingtransceiver unit. Details are not described again.

The base station may further include a memory, configured to store dataand program code. The processor may obtain the program code from thememory, and perform a corresponding procedure based on the obtainedprogram code.

According to the foregoing technical solutions, on a terminal side, theUE determines the first period used to periodically report the channelsounding information, and the UE periodically sends, based on thereceived preset DCI that is sent by the base station, the channelsounding information by using the first period as a sending period. On abase station side, the base station sends the preset DCI to the userequipment UE, and the base station receives the channel soundinginformation sent by the UE. System overheads can be reduced, aconfiguration response can be improved, and spectrum utilization of asystem can be improved while periodic feedback of indication is reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a flowchart of a channel sounding information feedback methodaccording to Embodiment 1 of the present disclosure;

FIG. 2 is a schematic diagram of a configuration time sequence by usinghigher layer RRC signaling according to Embodiment 1 of the presentdisclosure;

FIG. 3 is a schematic diagram of indicating periodic feedback by usingDCI according to Embodiment 1 of the present disclosure;

FIG. 4 is a flowchart of a channel sounding information feedback methodaccording to Embodiment 2 of the present disclosure;

FIG. 5 is a flowchart of a channel sounding information feedback methodaccording to Embodiment 3 of the present disclosure;

FIG. 6 is a flowchart of a channel sounding information feedback methodaccording to Embodiment 4 of the present disclosure;

FIG. 7 is a schematic diagram of structural components of user equipmentaccording to Embodiment 8 of the present disclosure; and

FIG. 8 is a schematic diagram of structural components of a base stationaccording to Embodiment 9 of the present disclosure.

DESCRIPTION OF EMBODIMENTS

The technical solutions of the present disclosure may be applicable tovarious communications systems, such as a GSM system, a Code DivisionMultiple Access (CDMA) system, a Wideband Code Division Multiple Access(WCDMA) system, a general packet radio service (GPRS) system, and a LongTerm Evolution (LTE) system.

User equipment (UE), also referred to as a mobile terminal, mobile userequipment, and the like, may communicate with one or more core networksthrough a radio access network (RAN) and the like. The user equipmentmay be a mobile terminal, such as a mobile phone (also referred to as a“cellular” phone) and a computer with a mobile terminal. For example,the user equipment may be a portable, pocket-sized, handheld, computerbuilt-in, or in-vehicle mobile apparatus, which exchanges languagesand/or data with the radio access network.

A base station may be a base transceiver station (BTS) in the GSM orCDMA, may be a NodeB in the WCDMA, or may be an evolved NodeB (eNB ore-NodeB) in LTE. This is not limited in the present disclosure.

Channel sounding information is obtained by UE by sounding an uplinktransmission channel and quantizing a sounding result and is reported bythe UE to a base station. The channel sounding information includes aCQI and/or an SRS. Feedback of the channel sounding information includestwo types: periodic feedback and aperiodic feedback. In an LTE standard,setting of a parameter of a sending period of periodic feedback isstipulated. Subsequently, the UE periodically sends the channel soundinginformation to the base station based on the sending period.

In the technical solutions provided in the embodiments of the presentdisclosure, the sending period is dynamically controlled by usingphysical layer signaling. First, a plurality of sending periods, forexample, a first period and a second period, are configured throughconfiguration on an RRC layer. Next, physical-layer downlinktransmission control signaling in an LTE communications system isdefined, and the defined downlink transmission control signaling is sentto the UE, so as to instruct the UE to dynamically switch a sendingperiod of the channel sounding information. In the technical solutionsprovided in the embodiments of the present disclosure, the parameter ofthe sending period stipulated in the standard is set to the firstperiod. In addition to the first period, in the technical solutionsprovided in the embodiments of the present disclosure, at least onesecond period is introduced. The sending period of reporting the channelsounding information by the UE is modified by using the at least onesecond period. One first period and one second period are used as anexample for detailed description.

Main implementation principles and specific implementations of thetechnical solutions of the embodiments of the present disclosure, andcorresponding beneficial effects that can be achieved thereby aredescribed below in detail with reference to the accompanying drawings.

Embodiment 1

Embodiment 1 of the present disclosure provides a channel soundinginformation feedback method. As shown in FIG. 1, a specific processingprocedure is as follows:

101: UE determines a first period of a report period used toperiodically send channel sounding information.

In 101, the UE receives system information of a serving cell, andconfigures the first period of the report period of the channel soundinginformation based on the received system information. A length and avalidity time (the validity time may be configured by using a timingtime of a timer) of the first period may be configured by using RRCsignaling. In a schematic diagram of a configuration time sequence shownin FIG. 2, a specific procedure of configuring the first period is: TheUE receives RRC signaling that is sent by a base station in an LTEcommunications system. The UE obtains a configuration in the RRCsignaling by receiving RRC connection setup. After obtaining theconfiguration in the RRC signaling, the UE determines the first period.The RRC signaling may be periodically changed or may be changed in apaging-triggered manner. For each change, a change notification needs tobe sent in a first modification period, and then the RRC configurationis updated in a next period close to the first modification period.

In the LTE communications system, when the channel sounding informationis a CQI, and when the UE determines a first period of the CQI, the UEconfigures the first period by receiving higher layer information, thatis, RRC connection setup and RRC connection reconfiguration. The higherlayer information received by the UE includes CQI-report config content,and a CQI-reportperiodic.cqi-pmi-configindex field is used to indicatethe first period of the CQI. Specifically, using an FDD communicationssystem as an example, the first period is obtained by using thefollowing Table 1, that is, a CQI periodic feedback configuration table.The UE queries Table 1, and feeds back the CQI to the base station on asubframe satisfying the following formula 1:(10×n _(f) +└n _(s)/2┘−N _(OFFSET,CQI))modN _(pd)=0  formula 1

In the formula 1, n_(f) is used to represent a number of a radio frame,and n_(s) represents a number of a timeslot in the radio frame. Afeedback parameter of the first period becomes valid in a radio frame inwhich this message is received.

TABLE 1 cqi-pmi-ConfigIndex CQI Periodicity Subframe Offset I_(CQI/PMI)N_(pd) N_(OFFSET) 0-1 2 I_(CQI/PMI) 2-6 5 I_(CQI/PMI) − 2   7-16 10I_(CQI/PMI) − 7  17-36 20 I_(CQI/PMI) − 17  37-76 40 I_(CQI/PMI) − 37  77-156 80 I_(CQI/PMI) − 77  157-316 160 I_(CQI/PMI) − 157 I_(CQI/PMI) =317 Reserved 318-349 32 I_(CQI/PMI) − 318 350-413 64 I_(CQI/PMI) − 350414-541 128 I_(CQI/PMI) − 414  542-1023 Reserved

In the LTE communications system, when the channel sounding informationis an SRS, and when the UE determines a first period of the SRS, the UEconfigures the first period by receiving SIB2, RRC connection setup andRRC connection reconfiguration that are sent by the base station. Higherlayer information received by the UE includessoundingRS-UL-configdedicated, and a srs-configinde field indicates thefirst period of reporting the SRS. Specifically, using an FDD system asan example, the first period of the SRS is obtained by using thefollowing Table 2. The UE queries Table 2, and selects a subframesatisfying the following formula 2 to send the SRS:(10·n _(f) +k _(SRS) −T _(offset))modT _(SRS)=0  formula 2

In the formula 2, n_(f) is used to represent a number of a radio frame,and k_(SRS)={0, 1, . . . , 9}. A parameter of the first period becomesvalid in a radio frame in which this message is received.

TABLE 2 srs-ConfigInde SRS Periodicity (ms) Subframe Offset I_(SRS)T_(SRS) T_(offset) 0-1 2 I_(SRS) 2-6 5 I_(SRS) − 2   7-16 10 I_(SRS) −7  17-36 20 I_(SRS) − 17 37-76 40 I_(SRS) − 37  77-156 80 I_(SRS) − 77157-316 160  I_(SRS) − 157 317-636 320  I_(SRS) − 317  637-1023 reservedreserved

Optionally, the method further includes the following steps:

101′: The UE determines a second period of the report period used toperiodically send the channel sounding information.

In the technical solution provided in Embodiment 1 of the presentdisclosure, when determining the report period used to periodically sendthe channel sounding information, the UE may determine the secondperiod.

Configuration information of the second period may include, but is notlimited to, indication information used to indicate the first period, ormay include configuration information of the first period.

The configuration information of the second period includes at least oneof the following information:

first: the configuration information of the second period includesinformation used to indicate a difference between the second period andthe first period;

second: the configuration information of the second period includes sameinformation as that of the first period; and

third: in the configuration information of the second period, at leastone digit may be reserved, and the at least one digit is used toindicate a case in which the sending period is null.

When the sending period is null, it indicates that the period does notexist.

102: A base station sends preset DCI to the UE.

The base station sends the preset DCI to the UE, to trigger the UE toaperiodically report the channel sounding information.

103: The UE receives the preset DCI sent by the base station.

104: The UE periodically sends, based on the received preset DCI that issent by the base station, the channel sounding information by using thefirst period as a sending period.

In the embodiments 101 to 104, the UE periodically sends, based on thereceived preset DCI that is sent by the base station, the channelsounding information by using the first period as a sending period. TheUE is triggered by the preset DCI, to periodically send the channelsounding information by using the first period as a sending period.

Correspondingly, after periodically sending the channel soundinginformation by using the first period as a sending period, the UE mayfurther stop periodically sending the channel sounding information byusing the first period as a sending period. A specific implementation isas follows:

A first implementation: The UE may be triggered based on the receivedpreset DCI, to stop periodically sending the channel soundinginformation by using the first period as a sending period. Specifically,the base station may preset the DCI for implementation.

In the first implementation, the UE determines indication information inthe received preset DCI. When the indication information is informationused to start the first period, the UE periodically sends the channelsounding information by using the first period as a sending period. Whenthe indication information is information used to end the first period,the UE stops periodically sending the channel sounding information byusing the first period as a sending period.

A second implementation: A first timer associated with the first periodis set for implementation.

In the second implementation, when periodically sending the channelsounding information by using the first period as a sending period, theUE simultaneously starts the first timer associated with the firstperiod. When the first timer expires, the UE stops periodically sendingthe channel sounding information by using the first period as a sendingperiod.

In the embodiments 101 to 104, the UE periodically sends the channelsounding information by using the first period as a sending period.Further, in 101′, the UE determines the second period, and then in 104,during specific implementation, the UE periodically sends the channelsounding information by using the first period and/or the second periodas a sending period. That is, if the UE has determined the first periodand the second period, when receiving the preset DCI, the UE mayperiodically send the channel sounding information by using the firstperiod as a sending period; or may periodically send the channelsounding information by using the second period as a sending period.Further, the UE may periodically send the channel sounding informationby using the first period and the second period as a sending periodsimultaneously.

Optionally, before 103, the method may further include:

periodically sending, by the UE, the channel sounding information byusing the first period as a sending period, and when the UE receives thepreset DCI, switching, by the UE, to periodically send the channelsounding information by using the second period as a sending period.

In this manner, when the UE does not receive the preset DCI that is sentby the base station, the UE sends the channel sounding information byusing the first period as a sending period. When the UE receives thepreset DCI that is sent by the base station, the UE switches toperiodically send the channel sounding information by using the secondperiod as a sending period. That is, the preset DCI received by the UEis an implementation of ending the first period and triggering to startthe second period.

Further, the channel sounding information sent by using the secondperiod differs from the channel sounding information sent by using thefirst period, and a priority of the channel sounding information sent byusing the second period is greater than a priority of the channelsounding information sent by using the first period. Therefore, if theUE needs to send the channel sounding information by using the firstperiod and the second period as a sending period separately at a samemoment, the UE switches to send the channel sounding informationcorresponding to the second period at the moment by using the secondperiod as a sending period.

An example is used for detailed description. It is assumed that thefirst period is 3 ms, and the second period is 2 ms. Timing is startedfrom the 0^(th) ms, the UE sends channel sounding information once at amultiple of 2 ms, and the UE sends channel sounding information once ata multiple of 3 ms. At the 6^(th) millisecond, the UE needs to send thechannel sounding information by using the multiple of 2 ms. In addition,at the 6^(th) millisecond, the UE further needs to send the channelsounding information by using the multiple of 3 ms. In this case, thepriority of the channel sounding information sent by using the secondperiod is greater than the priority of the channel sounding informationsent by using the first period, and the UE switches to send the channelsounding information by using the multiple of 2 ms. For the case inwhich at the 6^(th) millisecond, the UE needs to send the channelsounding information by using the multiple of 3 ms, the UE may stopsending the channel sounding information by using the multiple of 3 ms,or the UE delays sending the channel sounding information by using themultiple of 3 ms.

The priority of the channel sounding information sent by using thesecond period is greater than the priority of the channel soundinginformation sent by using the first period. During specificimplementation, in one manner, the priority may be determined based onaccuracy of the channel sounding information sent in the two periods.For example, accuracy of the channel sounding information sent in thesecond period is greater than accuracy of the channel soundinginformation sent in the first period. The example in which the firstperiod is 3 ms and the second period is 2 ms is still used. At the6^(th) millisecond, the priority of the channel sounding informationsent by using the second period is greater than the priority of thechannel sounding information sent by using the first period, and the UEmay stop sending the channel sounding information by using the multipleof 3 ms. In this way, more accurate channel sounding information can bereported. During specific implementation, in another manner, thepriority may be determined based on comprehensiveness of the channelsounding information. For example, when the channel sounding informationis SRS information, wider bandwidth of fed back SRS informationindicates a higher priority of a corresponding period of sending the SRSinformation.

In the foregoing method procedure, the UE periodically sends the channelsounding information by using the first period and/or the second periodas a sending period. During specific implementation, the UE determinesindication information in the received preset DCI. The indicationinformation is used to indicate the first period and/or the secondperiod. When the indication information is information used to start thefirst period and/or the second period, the UE periodically sends thechannel sounding information by using the first period and/or the secondperiod as a sending period.

The method may further include:

when the indication information is used to disable feedback of thechannel sounding information, and the UE uses the second period as asending period, restoring, by the UE, to periodically send the channelsounding information by using the first period as a sending period.

The method may further include:

when the indication information is used to disable feedback of thechannel sounding information, and the UE uses the first period as asending period, stopping, by the UE, sending the channel soundinginformation by using the first period as a sending period.

In the technical solution provided in Embodiment 1 of the presentdisclosure, the indication information is carried by using a field inthe preset DCI, and the field in the preset DCI includes at least one ofthe following:

A: a downlink assignment index DAI field of the DCI;

B: a resource block assignment field in DCI format 1A control signaling,where if the preset DCI is the resource block assignment field in theDCI format 1A control signaling, and a value in the resource blockassignment field is a specified value, designated location informationin an MCS field in the DCI format 1A control signaling is obtained, andthe designated location information is used as the indicationinformation; and

C: a CSI request field and an SRS request field in a DCI format 0 and/orthe DCI format 4.

If the preset DCI is the CSI request field and the SRS request field inthe DCI format 0 and/or the DCI format 4, the UE triggers aperiodicchannel sounding information once. After sending the aperiodic channelsounding information, the UE periodically sends the channel soundinginformation by using the first period and/or the second period as asending period. In the technical solution provided in Embodiment 1 ofthe present disclosure, for a case of aperiodic feedback of the channelsounding information, trigger binding of periodic feedback and theaperiodic feedback may be configured by using higher layer signaling.Through configuration by using the higher layer signaling, whenreceiving an aperiodic trigger instruction, the UE may report thechannel sounding information in an aperiodic feedback manner. If thisbinding manner is not configured in the higher layer signaling, afterreceiving an SCI/SRS request, the UE does not feed back periodic channelsounding information.

In the technical solution provided in Embodiment 1 of the presentdisclosure, a plurality of different periodic feedback parameters, suchas the first period and the second period, of the channel soundinginformation are configured through configuration on an RRC layer, todefine LTE communication.

Physical layer downlink transmission control signaling in a system isused to instruct, by using transmission of the downlink transmissioncontrol signaling on a physical layer, the UE to dynamically switch thesending period of the channel sounding information, to implementfunctions such as enabling, acceleration, reduction, interrupt, anddisabling of periodic feedback of the channel sounding information, asshown in FIG. 3. If feedback frequency of the second period is higherthan feedback frequency of the first period, an effect of acceleratingfeedback of the channel sounding information by the UE is presented.Otherwise, if the feedback frequency of the second period is lower thanthe feedback frequency of the first period, a feedback effect ofreducing feedback of the channel sounding information by the UE ispresented. When a period of the second period is defined as 0, that is,no information is fed back, an interrupt effect of periodic feedback isachieved. If a current second period is interspersed within a periodicfeedback interval of the first period, effects such as enabling anddisabling are presented, so that system overheads can be reduced, aconfiguration response can be improved, and spectrum utilization of thesystem can be improved while periodic feedback of indication is reduced.

Embodiment 2

In a technical solution provided in Embodiment 2 of the presentdisclosure, a channel sounding information feedback method is furtherdescribed by using an example in which channel sounding information is aCQI or an SRS. As shown in FIG. 4, a specific processing procedure ofthe method is as follows:

401: UE determines a first period and a second period that are of areport period used to periodically send a CQI/an SRS.

For a specific implementation process of 401, refer to the detaileddescriptions of 101 in Embodiment 1, and details are not described inEmbodiment 2 of the present disclosure again.

402: The UE configures timers/a timer associated with the first periodand/or the second period.

In 402, the UE configures a first timer based on received systeminformation that is sent by a base station, and the first timer isassociated with the first period; and/or the UE configures a secondtimer based on the received system information that is sent by the basestation, and the second timer is associated with the second period.

In the technical solution provided in Embodiment 2 of the presentdisclosure, an example in which the UE configures the second timer basedon the received system information that is sent by the base station andthe second timer is associated with the second period is used fordetailed description. Specifically, an implementation of the first timerassociated with the first period is the same as an implementation of thesecond timer associated with the second period, and details are notdescribed.

When the UE periodically feeds back the CQI/SRS to the base station byusing the second period as a sending period, the associated second timeris started to start timing until the timing of the second timer ends.During this time, any trigger to the second timer cannot turn off orre-start the timer.

403: A base station sends preset DCI to the UE.

The base station sends the preset DCI to the UE, to trigger the UE toaperiodically send the CQI/SRS.

404: The UE receives the preset DCI.

405: The UE aperiodically feeds back the CQI/SRS to the base station.

406: The UE determines whether a current sending period of feeding backthe CQI/SRS to the base station is the same as the first period, and ifthe current sending period is the same as the first period, performs407, or if the current sending period is different from the firstperiod, performs 409.

407: The UE switches to periodically send the CQI/SRS by using thesecond period as a sending period, and starts a second timer associatedwith the second period.

408: When the second timer expires to end timing, the UE switches toperiodically send the CQI/SRS by using the first period as a sendingperiod.

409: The UE continues to maintain the current sending period toperiodically send the CQI/SRS.

In the foregoing method procedure, the second timer associated with thesecond period is used as an example for detailed description. Duringspecific implementation, for the first timer associated with the firstperiod, during specific implementation, that the UE periodically sendsthe channel sounding information by using the first period as a sendingperiod includes: starting, by the UE, the first timer, and when thefirst timer expires, stopping, by the UE, periodically sending thechannel sounding information by using the first period as a sendingperiod.

In the technical solution provided in Embodiment 2 of the presentdisclosure, the first period, the second period, the first timerassociated with the first period, and the second timer associated withthe second period are set, so that when the UE switches to send theCQI/SRS by using the second period as a sending period, the UE does notautomatically switch to send the CQI/SRS by using the first period as asending period, until the timing of the second timer associated with thesecond period ends, thereby triggering short periodic feedback of theCQI/SRS.

In the technical solution provided in Embodiment 2 of the presentdisclosure, a part in a specific implementation of sending the CQI/SRSby the UE by using the first period as a sending period same as that inthe specific implementation of sending the CQI/SRS by the UE by usingthe second period as a sending period is not described again, only theexample in which the UE is triggered to send the CQI/SRS by using thesecond period as a sending period is used for description.

Embodiment 3

In a technical solution provided in Embodiment 3 of the presentdisclosure, a channel sounding information feedback method is furtherdescribed by using an example in which channel sounding information is aCQI or an SRS. As shown in FIG. 5, a specific processing procedure ofthe method is as follows:

501: UE determines a first period and a second period that are of areport period used to periodically send a CQI/an SRS.

For a specific implementation process of 501, refer to the detaileddescriptions of 101 and 101′ in Embodiment 1, and details are notdescribed in Embodiment 3 of the present disclosure again.

502: A base station sends preset DCI to the UE.

The base station sends the preset DCI to the UE, to trigger the UE toaperiodically send the CQI/SRS.

An example in which the preset DCI may be a downlink assignment index(DAI) field of the DCI is used for detailed description. The basestation may instruct, by using a downlink assignment index field of DCIin downlink non-common reference signaling, the UE to periodically sendthe CQI/SRS by using the second period as a sending period.

It is stipulated in a standard that a DAI location of DCI is used toindicate bundled feedback acknowledgement/negative acknowledgement(ACK/NACK) information. During specific implementation of this step,when the ACK/NACK is not used, the base station may add, to the DAIlocation of the DCI, indication information used to indicate the secondperiod.

For example, 1-bit information in the DAI field may be extracted asindication signaling for enabling or disabling the UE to periodicallysend the CQI/SRS by using the second period as a sending period.Specifically, DAI field indication signaling shown in the followingTable 3 is used as an example.

TABLE 3 DAI field information Status 0 Enable 1 Disable

503: The UE receives the preset DCI sent by the base station.

504: The UE determines whether the DCI carries indication informationfor enabling or disabling the UE to periodically send the CQI/SRS byusing the second period as a sending period, and if a determining resultis yes, performs 505, or if a determining result is no, skipsprocessing.

The UE receives the DCI sent by the base station. If detecting that thebundled ACK/NACK is not currently used in the received DCI, the UEdetermines that the DAI field in the DCI carries the indicationsignaling for enabling or disabling the UE to periodically send theCQI/SRS by using the second period as a sending period.

505: The UE determines whether a sending period of periodically sendingthe CQI/SRS is the first period, and if a determining result is yes,performs 506, or if a determining result is no, performs 507.

506: If the UE uses the first period as a sending period, the UEswitches to periodically send the CQI/SRS by using the second period asa sending period.

507: If the UE does not use the first period as a sending period, the UEcontinues to maintain a current sending period to periodically send theCQI/SRS.

In 505 to 507, if the UE detects that the bundled feedback ACK/NACK isnot currently used in DCI that is received on a downlink controlchannel, it indicates that the DAI currently carries a triggerinstruction for periodically sending the CQI/SRS. In this case, ifreceived DAI field information is detected as 0, the UE stops sendingthe CQI/SRS to the base station by using the first period as a sendingperiod, and switches to send the CQI/SRS to the base station by usingthe second period as a sending period. If the received DAI fieldinformation is detected as 1, the UE stops periodically sending theCQI/SRS to the base station by using the second period as a sendingperiod currently, and restores to periodically send the CQI/SRS to thebase station by using the first period as a sending period.

In the technical solution provided in Embodiment 3, the informationcarried in the DAI field of the DCI is defined, to instruct the UE todynamically switch a sending period of the channel sounding information.

Embodiment 4

In a technical solution provided in Embodiment 4 of the presentdisclosure, a channel sounding information feedback method is furtherdescribed by using an example in which channel sounding information is aCQI or an SRS. As shown in FIG. 6, a specific processing procedure ofthe method is as follows:

601: UE determines a first period and a second period that are of areport period used to periodically send a CQI/an SRS.

For a specific implementation process of 601, refer to the detaileddescriptions of 101 in Embodiment 1, and details are not described inEmbodiment 4 of the present disclosure again.

602: A base station sends preset DCI to the UE.

The base station sends the preset DCI to the UE, to trigger the UE toaperiodically send the CQI/SRS.

The base station may instruct, by using DCI format 1A control signaling,the UE to periodically send the CQI/SRS by using the second period as asending period.

For example, the base station may instruct, by using the DCI format 1Acontrol signaling, to enable or disable the UE to periodically send theCQI/SRS by using the second period as a sending period. Unusedinformation in a resource block assignment field in a DCI format 1A isstipulated, for example, is all configured to 0 or 1, to indicate to theUE that the current control signaling is to instruct to enable/disablethe UE to periodically send the CQI/SRS by using the second period as asending period.

In the technical solution provided in Embodiment 4 of the presentdisclosure, the format 1A control signaling has sufficient informationbits. 1-bit information in any field may be extracted for indication.For example, as shown in Table 4, 1-bit information in an MCS field inthe format 1A is extracted for indication.

TABLE 4 First bit in the MCS field Status 0 Enable 1 Disable

603: The UE receives the DCI sent by the base station.

604: The UE determines whether the DCI carries indication signaling forenabling or disabling the UE to periodically send the CQI/SRS by usingthe second period as a sending period, and if a determining result isyes, performs 605, or if a determining result is no, skips processing.

For example, if detecting that information in a resource blockassignment field in a DCI format 1A received on a downlink controlchannel is all 0, the UE determines that the information is theindication signaling for enabling or disabling the UE to periodicallysend the CQI/SRS by using the second period as a sending period.

Alternatively, the information in the resource block assignment fieldmay all be 1, used as the indication signaling for enabling or disablingthe UE to periodically send the CQI/SRS by using the second period as asending period.

605: The UE continues to detect first-bit information in an MCS field ina DCI format 1A.

606: If received first-bit information in the MCS field is 0, the UEstops using the first period as a sending period, and switches toperiodically send the CQI/SRS by using the second period as a sendingperiod.

607: If received first-bit information in the MCS field is 1, the UEstops using the second period as a sending period, and switches toperiodically send the CQI/SRS by using the first period as a sendingperiod.

In the technical solution provided in Embodiment 4 of the presentdisclosure, the information carried in a DAI field of the DCI isdefined, to instruct the UE to dynamically switch a sending period ofthe channel sounding information.

Embodiment 5

In the foregoing Embodiment 2 to Embodiment 4, the specificimplementation procedure of the channel sounding information feedbackmethod is described by using an example in which channel soundinginformation is a CQI or an SRS. In a technical solution provided inEmbodiment 5 of the present disclosure, a channel sounding informationfeedback method is described in detail by using an example in whichchannel sounding information is a CQI and an SRS, that is, UE reportsboth the CQI and the SRS. A specific processing procedure of the methodis as follows:

First, UE determines a first period and a second period that are of areport period used to periodically send a CQI and an SRS.

For a specific implementation process of the first step, refer to thedetailed descriptions of 101 in Embodiment 1, and details are notdescribed in Embodiment 5 of the present disclosure again.

Second, the UE configures a timer associated with the second period.

In the second step, the UE configures the timer based on received systeminformation that is sent by a base station, and the timer is associatedwith the second period.

When the UE periodically feeds back the CQI and the SRS to the basestation by using the second period as a sending period, the timer isstarted to start timing until the timing of the second timer ends.During this time, any trigger to the timer cannot turn off or re-startthe timer.

Third, a base station sends DCI to the UE.

The base station sends the DCI to the UE, to trigger the UE toaperiodically send the CQI and the SRS.

The base station may instruct, by using a CQI request field and an SRSrequest field in a DCI format 0 and/or a DCI format 4 separately, the UEto periodically send the CQI and the SRS by using the second period as asending period.

For example, in an implementation, the UE may instruct, by using the CQIrequest field and the SRS request field that are configured in the DCIformat 0, the UE to periodically report the CQI and the SRS by using thesecond period as a sending period.

In an implementation, the UE may instruct, by using the CQI requestfield and the SRS request field that are configured in the DCI format 4,the UE to periodically report the CQI and the SRS by using the secondperiod as a sending period.

In an implementation, the UE may instruct, by using the CQI requestfield configured in the DCI format 0 and the SRS request fieldconfigured in the DCI format 4, the UE to periodically report the CQIand the SRS by using the second period as a sending period.

In an implementation, the UE may instruct, by using the CQI requestfield configured in the DCI format 4 and the SRS request fieldconfigured in the DCI format 0, the UE to periodically report the CQIand the SRS by using the second period as a sending period.

Fourth, the UE receives the DCI.

405: The UE aperiodically feeds back the CQI and the SRS to the basestation.

Sixth, the UE determines whether a current sending period of feedingback the CQI and the SRS to the base station is the same as the firstperiod, and if the current sending period is the same as the firstperiod, performs the sixth step, or if the current sending period isdifferent from the first period, performs the ninth step.

Seventh, the UE switches to periodically send the CQI and the SRS byusing the second period as a sending period, and starts the timerassociated with the second period.

Eighth, when the timer expires to end timing, the UE switches toperiodically send the CQI and the SRS by using the first period as asending period.

Ninth, the UE continues to maintain the current sending period toperiodically send the CQI and the SRS.

In the technical solution provided in Embodiment 5 of the presentdisclosure, the first period, the second period, and the timerassociated with the second period are set, so that when the UE switchesto send the CQI/SRS by using the second period as a sending period, theUE does not automatically switch to send the CQI and the SRS by usingthe first period as a sending period, until the timing of the timerassociated with the second period ends, thereby triggering shortperiodic feedback of the CQI and the SRS.

Embodiment 6

In a technical solution provided in Embodiment 6 of the presentdisclosure, a channel sounding information feedback method is furtherdescribed by using an example in which channel sounding information is aCQI and an SRS. A specific processing procedure of the method is asfollows:

First, UE determines a first period and a second period that are of areport period used to periodically send a CQI and an SRS.

For a specific implementation process of the first step, refer to thedetailed descriptions of 101 in Embodiment 1, and details are notdescribed in Embodiment 6 of the present disclosure again.

Second, a base station sends DCI to the UE.

The base station sends the DCI to the UE, to trigger the UE toaperiodically send the CQI and the SRS.

The base station may instruct, by using a downlink assignment index(DAI) field of DCI in downlink non-common reference signaling, the UE toperiodically send the CQI/SRS by using the second period as a sendingperiod. When the DAI of the DCI carries a bundled feedbackacknowledgement/negative acknowledgement (ACK/NACK), the base stationadds indication information used to indicate the second period to theDAI field.

For example, 2-bit information in the DAI field may be extracted asindication signaling for enabling or disabling the UE to periodicallysend the CQI and the SRS by using the second period as a sending period.Specifically, DAI field indication signaling shown in the followingTable 5 is used as an example.

TABLE 5 DAI field information Status 00 Enable the CQI, and enable theSRS 01 Enable the CQI, and disable the SRS 10 Disable the CQI, andenable the SRS 11 Disable the CQI, and disable the SRS

Third, the UE receives the DCI sent by the base station.

Fourth, the UE determines whether the DCI carries indication signalingfor enabling or disabling the UE to periodically send the CQI and theSRS by using the second period as a sending period, and if a determiningresult is yes, performs the fifth step, or if a determining result isno, skips processing.

The UE receives the DCI sent by the base station. If detecting that thebundled ACK/NACK is not currently used in the received DCI, the UEdetermines that the DAI field in the DCI carries the indicationsignaling for enabling or disabling the UE to periodically send the CQIand the SRS by using the second period as a sending period.

Fifth, the UE determines whether a sending period of periodicallysending the CQI and the SRS is the first period, and if a determiningresult is yes, performs the sixth step, or if a determining result isno, performs the seventh step.

Sixth, if the UE uses the first period as a sending period, the UEswitches to periodically send the CQI and the SRS by using the secondperiod as a sending period.

Seventh, if the UE does not use the first period as a sending period,the UE continues to maintain a current sending period to periodicallysend the CQI and the SRS.

In the fifth to the seventh steps, if the UE detects that the bundledfeedback ACK/NACK is not currently used in DCI that is received on adownlink control channel, it indicates that the DAI currently carries atrigger instruction for periodically sending the CQI and the SRS. Inthis case, if received DAI field information is detected as 0, the UEstops sending the CQI and the SRS to the base station by using the firstperiod as a sending period, and switches to send the CQI and the SRS tothe base station by using the second period as a sending period. If thereceived DAI field information is detected as 1, the UE stopsperiodically sending the CQI and the SRS to the base station by usingthe second period as a sending period currently, and restores toperiodically send the CQI and the SRS to the base station by using thefirst period as a sending period. Further, the UE may determine, basedon the information carried in the DAI field, whether to periodicallysend the CQI and the SRS simultaneously by using the second period as asending period, or to periodically send the CQI and the SRS separatelyby using the second period as a sending period.

In the technical solution provided in Embodiment 6, the informationcarried in the DAI field of the DCI is defined, to instruct the UE todynamically switch a sending period of the channel sounding information.

Embodiment 7

In a technical solution provided in Embodiment 7 of the presentdisclosure, a channel sounding information feedback method is furtherdescribed by using an example in which channel sounding information is aCQI and an SRS. A specific processing procedure of the method is asfollows:

First, UE determines a first period and a second period that are of areport period used to periodically send a CQI/an SRS.

For a specific implementation process of the first step, refer to thedetailed descriptions of 101 in Embodiment 1, and details are notdescribed in Embodiment 7 of the present disclosure again.

Second, a base station sends DCI to the UE.

The base station sends the DCI to the UE, to trigger the UE toaperiodically send the CQI/SRS.

The base station may instruct, by using DCI format 1A control signaling,the UE to periodically send the CQI and the SRS by using the secondperiod as a sending period.

For example, the base station may instruct, by using the DCI format 1Acontrol signaling, to enable or disable the UE to periodically send theCQI and the SRS by using the second period as a sending period. Unusedinformation in a resource block assignment field in a DCI format 1A isstipulated, for example, is all configured to 0 or 1, to indicate to theUE that the current control signaling is to instruct to enable/disablethe UE to periodically send the CQI and the SRS by using the secondperiod as a sending period. In the technical solution provided inEmbodiment 7 of the present disclosure, the format 1A control signalinghas sufficient information bits. 2-bit information in any field may beextracted for indication. For example, as shown in Table 4, 2-bitinformation in an MCS field in the format 1A is extracted forindication.

TABLE 6 First two bits in the MCS field Status 00 Enable the CQI, andenable the SRS 01 Enable the CQI, and disable the SRS 10 Disable theCQI, and enable the SRS 11 Disable the CQI, and disable the SRS

Third, the UE receives the DCI sent by the base station.

Fourth, the UE determines whether the DCI carries indication signalingfor enabling or disabling the UE to periodically send the CQI and theSRS by using the second period as a sending period, and if a determiningresult is yes, performs the fifth step, or if a determining result isno, skips processing.

For example, if detecting that information in a resource blockassignment field in a DCI format 1A received on a downlink controlchannel is all 0, the UE determines that the information is theindication signaling for enabling or disabling the UE to periodicallysend the CQI and the SRS by using the second period as a sending period.

Alternatively, the information in the resource block assignment fieldmay all be 1, used as the indication signaling for enabling or disablingthe UE to periodically send the CQI/SRS by using the second period as asending period.

Fifth, the UE continues to detect first-bit information in an MCS fieldin the DCI format 1A.

Sixth, if received first-bit information in the MCS field is 0, the UEstops using the first period as a sending period, and switches toperiodically send the CQI/SRS by using the second period as a sendingperiod.

Seventh, if received first-bit information in the MCS field is 1, the UEstops using the second period as a sending period, and switches toperiodically send the CQI/SRS by using the first period as a sendingperiod.

In the technical solution provided in Embodiment 7 of the presentdisclosure, the information carried in the DAI field of the DCI isdefined, to instruct the UE to dynamically switch a sending period ofthe channel sounding information.

Embodiment 8

Embodiment 8 of the present disclosure provides user equipment. As shownin FIG. 7, the user equipment includes a processing unit 701 and atransceiver unit 702.

The processing unit 701 is configured to determine a first period usedto periodically report channel sounding information.

The transceiver unit 702 is configured to receive preset downlinkcontrol information DCI that is sent by a base station.

The processing unit 701 is further configured to periodically send, byusing the transceiver unit 702 and by the UE based on the receivedpreset downlink control information DCI that is sent by the basestation, the channel sounding information by using the first period as asending period.

Optionally, the processing unit 701 is further configured to: determinea second period used to periodically report channel soundinginformation; and periodically send, by using the transceiver unit, thechannel sounding information by using the first period and/or the secondperiod as a sending period.

Optionally, the processing unit 701 is further configured to: before thepreset DCI is received, periodically send, by using the transceiverunit, the channel sounding information by using the first period as asending period; and after the preset DCI is received, switch toperiodically send the channel sounding information by using the secondperiod as a sending period.

A priority of the channel sounding information sent by using the secondperiod is greater than a priority of the channel sounding informationsent by using the first period. The processing unit 701 is specificallyconfigured to: if the UE needs to send the channel sounding informationby using the first period and the second period as a sending periodseparately at a same moment, switch, by the UE, to send the channelsounding information corresponding to the second period at the moment byusing the second period as a sending period.

Specifically, the processing unit 701 is configured to configure a firsttimer associated with the first period and/or a timer associated withthe second period.

Specifically, the processing unit 701 is specifically configured to:start the second timer; and when the second timer expires, stopperiodically sending the channel sounding information by using thesecond period as a sending period, and restore to periodically send thechannel sounding information by using the first period as a sendingperiod.

Specifically, the processing unit 701 is specifically configured to:start the first timer; and when the first timer expires, stopperiodically sending the channel sounding information by using the firstperiod as a sending period.

Specifically, the processing unit 701 is specifically configured to:determine indication information in the received preset DCI, where theindication information is used to indicate the first period and/or thesecond period; and when the indication information is information usedto start the first period and/or the second period, periodically sendthe channel sounding information by using the first period and/or thesecond period as a sending period.

Specifically, the processing unit 701 is specifically configured to:when the indication information is used to disable feedback of thechannel sounding information, and the UE uses the second period as asending period, restore to periodically send the channel soundinginformation by using the first period as a sending period.

Specifically, the processing unit 701 is further configured to: when theindication information is used to disable feedback of the channelsounding information, and the UE uses the first period as a sendingperiod, stop sending the channel sounding information by using the firstperiod as a sending period.

The preset DCI received by the transceiver unit includes at least one ofthe following: a downlink assignment index DAI field of the DCI, aresource block assignment Resource block assignment field in the DCIformat Format 1A control signaling, and a CSI request field and an SRSrequest field in the DCI format 0 and/or the DCI format 4.

Specifically, the processing unit 701 is specifically configured to: ifthe preset DCI is the resource block assignment field in the DCI format1A control signaling, and a value in the resource block assignment fieldis a specified value, obtain designated location information in amodulation and coding scheme MCS field in the DCI format 1A controlsignaling; and use the designated location information as the indicationinformation.

Specifically, the processing unit 701 is specifically configured to: ifthe preset DCI is the CSI request field and the SRS request field in theDCI format 0 and/or the DCI format 4, trigger, by the UE, aperiodicchannel sounding information once; and after the aperiodic channelsounding information is sent, periodically send, by the UE, the channelsounding information by using the first period and/or the second periodas a sending period.

Specifically, the channel sounding information sent by the processingunit 701 by using the transceiver unit includes a channel soundinginformation indicator CQI and/or a channel sounding reference signalSRS.

Correspondingly, an embodiment of the present disclosure furtherprovides user equipment, including a transceiver and a processor. Forspecific implementation of the transceiver, refer to the detaileddescriptions of the foregoing transceiver unit, and details are notdescribed herein again. The transceiver may include an interface. Theinterface may be one or more of the following: a network interfacecontroller (NIC for short) provided with a wired interface, such as anEthernet NIC, where the Ethernet NIC can provide a copper-wired and/orfiber interface; and a NIC provided with a wireless interface, such as awireless local area network (WLAN for short) NIC.

The user equipment may further include a memory, configured to storedata and program code. The memory may be a volatile memory such as arandom access memory (RAM for short); or a nonvolatile memory such as aflash memory, a hard disk drive (HDD for short), or a solid-state drive(SSD for short); or a combination of such types of memories.

For specific implementation of the processor, refer to the detaileddescriptions of the foregoing processing unit, and details are notdescribed herein again. The processor may be a central processing unit(CPU for short), or a combination of a CPU and a hardware chip. A signalprocessing unit may also be a network processing unit (NP for short), acombination of a CPU and an NP, or a combination of an NP and a hardwarechip.

The hardware chip may be one or a combination of the following: anapplication-specific integrated circuit (ASIC for short), afield-programmable gate array (FPGA for short), and a complexprogrammable logic device (CPLD for short).

Correspondingly, Embodiment 9 of the present disclosure further providesa base station. As shown in FIG. 8, the base station includes aprocessing unit 81 and a transceiver unit 82.

The processing unit 81 is configured to: preset downlink controlinformation DCI; send the preset downlink control information DCI touser equipment UE by using the transceiver unit 82; and receive channelsounding information sent by the UE, where the channel soundinginformation is periodically sent by the UE by using a first periodand/or a second period as a sending period, and the first period and thesecond period are a sending period used by the UE to send the channelsounding information.

Specifically, the processing unit 81 is specifically configured to sendthe preset DCI to the UE by using the transceiver unit 82, where thepreset DCI includes indication information, and the indicationinformation is used to indicate the first period and/or the secondperiod.

Specifically, the indication information sent by the transceiver unit 82includes one of the following: information used to start the firstperiod and/or the at least one second period; and information used toend the first period and/or the at least one second period.

The preset DCI includes a downlink assignment index DAI field of theDCI. Specifically, the processing unit 81 is specifically configured tosend the preset DCI to the UE, where when the DAI field of the DCI doesnot carry a bundled feedback acknowledgement/negative acknowledgementACK/NACK, the base station sets the DAI field to carry the indicationinformation used to indicate feedback of the channel soundinginformation.

The preset DCI includes a resource block assignment Resource blockassignment field in the DCI format Format 1A control signaling. Theprocessing unit 81 is specifically configured to: set a value in theresource block assignment field in the DCI format 1A control signalingto a specified value; set designated bit information in a modulation andcoding scheme MCS field in the DCI format 1A control signaling, wherethe specified value and the designated bit information are used toindicate the indication information for indicating the first periodand/or the second period; and send the DCI format 1A control signalingcarrying the indication information to the UE.

The preset DCI includes a CSI request field and an SRS request field ina DCI format 0 and/or the DCI format 4. The processing unit 81 isspecifically configured to: set the CSI request field and the SRSrequest field in the DCI format 0 and/or the DCI format 4 controlsignaling to a specified value, where the specified value is theindication information for indicating the first period and/or the secondperiod; and send the DCI format 0 and/or DCI format 4 control signalingcarrying the indication information to the UE.

Specifically, the channel sounding information received by thetransceiver unit 82 includes a channel sounding information indicatorCQI and/or a channel sounding reference signal SRS.

In the base station provided in this embodiment of the presentdisclosure, the transceiver unit 82 may be implemented by using atransceiver, the transceiver includes an interface, and the interfacemay be one or more of the following: a NIC provided with a wiredinterface, such as an Ethernet NIC, where the Ethernet NIC may provide acopper-wired and/or fiber interface; and a NIC provided with a wirelessinterface, such as a WLAN NIC.

The base station provided in this embodiment of the present disclosuremay further include a memory, configured to store data and program code.

The memory may be a volatile memory such as a RAM; or a non-volatilememory such as a flash memory, an HDD, or an SSD; or a combination ofsuch types of memories.

For specific implementation of the processor, refer to the detaileddescriptions of the foregoing processing unit, and details are notdescribed herein again.

The processor may be a CPU or a combination of a CPU and a hardwarechip; or may be an NP or a combination of a CPU and an NP; or acombination of an NP and a hardware chip.

The hardware chip may be one or a combination of the following: an ASIC,an FPGA, and a CPLD.

A person skilled in the art should understand that the embodiments ofthe present disclosure may be provided as a method, an apparatus(device), or a computer program product. Therefore, the presentdisclosure may use a form of hardware only embodiments, software onlyembodiments, or embodiments with a combination of software and hardware.Moreover, the present disclosure may use a form of a computer programproduct that is implemented on one or more computer-usable storage media(including but not limited to a disk memory, a compact disc read-onlymemory, an optical memory, and the like) that include computer-usableprogram code.

The present disclosure is described with reference to the flowchartsand/or block diagrams of the method, the apparatus (device), and thecomputer program product according to the embodiments of the presentdisclosure. It should be understood that computer program instructionsmay be used to implement each process and/or each block in theflowcharts and/or the block diagrams and a combination of a processand/or a block in the flowcharts and/or the block diagrams. Thesecomputer program instructions may be provided for a general-purposecomputer, a specific-purpose computer, an embedded processor, or anyother programmable data processing device to generate a machine, so thatthe instructions executed by a computer or any other programmable dataprocessing device generate an apparatus for implementing a specificfunction in one or more processes in the flowcharts and/or in one ormore blocks in the block diagrams.

These computer program instructions may also be stored in acomputer-readable memory that can instruct the computer or any otherprogrammable data processing device to work in a specific manner, sothat the instructions stored in the computer-readable memory generate anartifact that includes an instruction apparatus. The instructionapparatus implements a specific function in one or more processes in theflowcharts and/or in one or more blocks in the block diagrams.

These computer program instructions may also be loaded onto a computeror another programmable data processing device, so that a series ofoperations and steps are performed on the computer or the anotherprogrammable device, thereby generating computer-implemented processing.Therefore, the instructions executed on the computer or the anotherprogrammable device provide steps for implementing a specific functionin one or more processes in the flowcharts and/or in one or more blocksin the block diagrams.

Although some preferred embodiments of the present disclosure have beendescribed, a person skilled in the art can make changes andmodifications to these embodiments once they learn the basic inventiveconcept. Therefore, the following claims are intended to be construed ascovering the preferred embodiments and all changes and modificationsfalling within the scope of the present disclosure.

Obviously, a person skilled in the art can make various modificationsand variations to the present disclosure without departing from thespirit and scope of the present disclosure. The present disclosure isintended to cover these modifications and variations provided that theyfall within the scope of protection defined by the following claims andtheir equivalent technologies.

What is claimed is:
 1. A method, comprising: sending first indicationinformation to user equipment (UE), which is carried by downlink controlinformation (DCI); receiving first channel sounding informationperiodically sent by the UE in a first period, wherein the first periodis triggered by the first indication information; and receiving secondchannel sounding information periodically sent by the UE in a secondperiod, wherein the second channel sounding information is differentfrom the first channel sounding information; and, wherein a priority ofthe channel sounding information sent in the second period is greaterthan a priority of the channel sounding information sent in the firstperiod.
 2. The method according to claim 1, wherein: the firstindication information is configured for indicating to the UE to switchto periodically send the second channel sounding information in thesecond period as a sending period; or the first indication informationis configured for indicating to the UE to periodically send the firstchannel sounding information in the first period as a sending period,and/or to periodically send the second channel sounding information inthe second period as a sending period.
 3. The method according to claim1, further comprising: sending second indication information to the UEfor disabling reporting of channel sounding information.
 4. The methodaccording to claim 1, wherein the first indication information iscarried by a field in the DCI comprising at least one of the following:a resource block assignment field in the DCI; and a designated locationinformation in a modulation and coding scheme (MCS) field in the DCI,wherein a value in a resource block assignment field in the DCI is aspecified value.
 5. The method according to claim 1, wherein the DCI isa preset DCI.
 6. The method according to claim 1, wherein the firstchannel sounding information comprises a channel quality informationindicator (CQI) and/or a channel sounding reference signal (SRS).
 7. Themethod according to claim 1, wherein the second channel soundinginformation comprises a channel quality information indicator (CQI)and/or a channel sounding reference signal (SRS).
 8. A non-transitorycomputer-readable medium having program instructions recorded thereon,wherein, when executed by at least one processor of a terminal device,the instructions cause the terminal device to: determine a first periodused to periodically send first channel sounding information; receivefirst indication information carried by downlink control information(DCI) sent by a base station; and periodically send, according to thefirst indication information, the first channel sounding information byusing the first period as a sending period; send second channel soundinginformation in a second period, wherein the second channel soundinginformation is different from the first channel sounding information;and when the first period and the second period overlaps, switch to sendthe second channel sounding information in the second period and not tosend the first channel sounding information in the first period, whereina priority of the channel sounding information sent in the second periodis greater than a priority of the channel sounding information sent inthe first period.
 9. The non-transitory computer-readable mediumaccording to claim 8, wherein: the first indication information isconfigured for indicating to the UE to switch to periodically send thesecond channel sounding information in the second period as a sendingperiod; or the first indication information is configured for indicatingto the UE to periodically send the first channel sounding information inthe first period as a sending period, and/or to periodically send thesecond channel sounding information by using the second period as asending period.
 10. The non-transitory computer-readable mediumaccording to claim 8, wherein the instructions further cause theterminal device to: receive second indication information sent by thebase station; when the second indication information is configured fordisabling reporting of channel sounding information, stop sending thefirst channel sounding information by using the first period as asending period.
 11. The non-transitory computer-readable mediumaccording to claim 8, wherein the indication information is carried byusing a field in the DCI comprising at least one of the following: aresource block assignment field in the DCI; and a designated locationinformation in a modulation and coding scheme (MCS) field in the DCI,wherein a value in a resource block assignment field in the DCI is aspecified value.
 12. The non-transitory computer-readable mediumaccording to claim 8, wherein the first channel sounding informationcomprises a channel quality information indicator (CQI) and/or a channelsounding reference signal (SRS).
 13. The non-transitorycomputer-readable medium according to claim 8, wherein the DCI is presetDCI.
 14. A non-transitory computer-readable medium having programinstructions recorded thereon, wherein, when executed by at least oneprocessor of a base station, the instructions cause the base station to:send first indication information to user equipment (UE), which iscarried by downlink control information (DCI); receive first channelsounding information periodically sent by the UE in a first period,wherein the first period is trigger by the first indication information;and receive second channel sounding information periodically sent by UEin a second period, wherein the second channel sounding information isdifferent from the first channel sounding information; and, wherein apriority of the channel sounding information sent in the second periodis greater than a priority of the channel sounding information sent inthe first period.
 15. The non-transitory computer-readable mediumaccording to claim 14, wherein: the first indication information isconfigured for indicating the UE to switch to periodically send thesecond channel sounding information in the second period as a sendingperiod; or the first indication information is configured for indicatingthe UE to periodically send the first channel sounding information byusing the first period as a sending period, and/or to periodically sendthe second channel sounding information by using the second period as asending period.
 16. The non-transitory computer-readable mediumaccording to claim 14, wherein the instructions further cause the basestation to: send second indication information to the UE for disablingreporting of channel sounding information.
 17. The non-transitorycomputer-readable medium according to claim 14, wherein the firstindication information is carried by using a field in the DCI; and thefield in the DCI comprises at least one of the following: a resourceblock assignment field in the DCI; and a designated location informationin the modulation and coding scheme (MCS) field in the DCI, wherein avalue in a resource block assignment field in the DCI is a specifiedvalue.
 18. The non-transitory computer-readable medium according toclaim 14, wherein the DCI is a preset DCI.
 19. The non-transitorycomputer-readable medium according to claim 14, wherein the firstchannel sounding information comprises a channel quality informationindicator (CQI) and/or a channel sounding reference signal (SRS). 20.The non-transitory computer-readable medium according to claim 14,wherein the second channel sounding information comprises a channelquality information indicator (CQI) and/or a channel sounding referencesignal (SRS).